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the ratio of the ultimate capacity to the magnitude of the demand at the service level.
load, multiplied by appropriate load factors, used to proportion members by the strength-design method.
the rapid development of rigidity in a freshly mixed portland cement paste, mortar, or concrete without the evolution of much heat, which rigidity can be dispelled and plasticity regained by further mixing without addition of water. (See also flash settin
the weakening of a material by repeated loads.
rupture of a material, when subjected to repeated loadings, at a stress substantially less than the static strength.
the greatest stress that can be sustained for a given number of stress cycles without failure.
differential displacement of a slab or wall along a joint or crack.
the edge of a concrete or mortar patch or topping that is beveled at an acute angle.
material distributor or regulator in certain types of shotcrete equipment.
a slender and elongated solid material, generally with a length at least 100 times its diameter.
the number of fibers in a unit volume of fiber-reinforced concrete.
concrete containing dispersed, randomly oriented fibers.
concrete delivered to or mixed, placed, and cured on the job site.
test cylinders that are left at the job site for curing as nearly as practicable in the same manner as the concrete in the structure to indicate when supporting forms may be removed, additional construction loads may be imposed, or the structure may be pl
a hydraulic-cement grout batched at the job site using water and predetermined portions of hydraulic cement, aggregate, and other ingredients.
(1) a finely divided, relatively inert material (such as pulverized limestone, silica, or colloidal substances) added to portland cement, paint, resin, or other materials to reduce shrinkage, improve workability, reduce cost, or reduce density; (2) mater
(1) a narrow linear projection on a formed concrete surface, resulting from mortar flowing into spaces in the formwork; (2) a type of blade in a concrete mixer drum.
deliberate action taken between the final finishing and termination of curing to reduce the loss of water from the surface of the concrete and control the temperature of the concrete.
a degree of stiffening of a cementitious mixture greater than initial setting, generally stated as an empirical value indicating the time required forthe cementitious mixture to stiffen sufficiently to resist, to an establisheddegree, the penetration of a
the time required for a freshly mixed cement paste, mortar, or concrete toachieve final set. (See also initial setting time.)
(1) aggregate passing the 9.5 mm (3/8 in.) sieve, almost entirely passing the 4.75 mm (No. 4) sieve, and predominantly retained on the 75 mm(No. 200) sieve; (2) that portion of aggregate passing the 4.75 mm (No. 4) sieve and predominantly retained on the
soil in which the smaller grain sizes predominate, such as fine sand, silt,and clay.
a measure of particle size.
a factor obtained by adding the total percentages of material in the sample that are coarser than each of the following sieves (cumulative percentages retained), and dividing the sum by 100: 150 m m (No. 100), 300 m m (No.50), 600 m m (No. 30), 1.18 mm (N
the texture of a concrete surface after consolidating and finishingoperations have been performed.
(1) final thin coat of shotcrete in preparation for hand finishing; (2) finalexposed coat of plaster or stucco.
(1) the final grinding of clinker into cement, with calcium sulfate in the form of gypsum or anhydrite generally being added; (2) the final grinding operation required for a finished concrete surface, for example, bump cutting of pavement, fin removal fr
vibrating horizontal screens operated at a batching plant so that anexcessive amount of significant undersize material is removed.
leveling, smoothing, consolidating, and otherwise treating surfaces offresh or recently placed concrete or mortar to produce desired appearance and service. (See also float and trowel.)
a power-operated machine used to produce the desired surface texture on a concrete slab.
an earthy or stony mineral aggregate that has as the essential constituent hydrous silicates of aluminum with or without free silica and that is plastic when sufficiently pulverized and wetted, rigid when subsequently dried, and of suitable refractoriness
(1) the property of a material or assembly to withstand fire or give protection from it; (2) the ability of building elements to confine a fire or, when exposed to fire, to continue to perform a given structural function, or both.
the compressive or flexural strength of refractory concrete determined upon cooling after first firing to a specified temperature for a specified time.
a thin coat of shotcrete used to cover minor blemishes on a concrete surface.
the rapid development of rigidity in a freshly mixed portland cement paste, mortar, or concrete, characteristically with the evolution of considerable heat, which rigidity cannot be dispelled nor can the plasticity be regained by further mixing without ad
a thin impermeable sheet (narrow in comparison with its length) installed as a cover to exclude water from exposed joints and at roof valleys, hips, parapets, or intersections of roof and chimney.
a concrete slab reinforced in two or more directions and having drop panels, column capitals, or both. (See also flat plate.)
a pavement structure that maintains intimate contact with and distributes loads to the subgrade and depends on aggregate interlock, particle friction, and cohesion for stability.
in structural-concrete members, the stress between the concrete and the reinforcing element that results from the application of external load.
a measure of stiffness of a member, indicated by the product of modulus of elasticity and moment of inertia divided by the length of the member.
the measured maximum resistance of a concrete specimen to flexural loading and reported as modulus of rupture. (See also modulus of rupture.)
a variety of chert. (See also chert.)
a tool (not a darby), usually of wood, aluminum, or magnesium used in finishing operations to impart a relatively even but still open texture to an unformed fresh concrete surface. (See also darby.)
a rough, granular concrete surface texture obtained by finishing with a float.
smoothing and subsequent compaction and consolidation of the unformed concrete surface.
(1) time-dependent irrecoverable deformation (see also creep); (2) a measure of the consistency of freshly mixed concrete, mortar, or cement paste expressed in terms of the increase in diameter of a molded truncated cone specimen after jigging a specifie
a flat, circular jigging device used in making flow tests for consistency ofcement paste, mortar, or concrete. (See also flow [2].)
a sloping trough used to convey concrete by gravity flow from either a truck mixer or a receiving hopper to the point of placement. (See also chute. )
a cohesive concrete mixture with a slump greater than 7-1/2 in. (190 mm).
(1) the consistency at which a grout will form a nearly level surface without vibration or rodding; (2) the consistency of a grout that has an efflux time of less than 30 seconds through an ASTM C939 flow cone.
an admixture employed in grout to increase fluidity without changingwater content. (See also water-reducing admixture.)
the finely divided residue that results from the combustion of ground or powdered coal and that is transported by flue gases from the combustion zone to the particle removal system.
low-density concrete made by the addition of a prepared foam or by generation of gas within the fresh mixture.
(1) storage of concrete in a moist room in which the desired high humidity is achieved by the atomization of water (see also moist room); (2) application of atomized water to concrete, stucco, mortar, or plaster.
see moist room (preferred term).
a structural element of a foundation that transmits loads directly to the soil.
a temporary structure or mold for the support of concrete while it is settingand gaining sufficient strength to be self-supporting. (See also formwork.)
device used to secure formwork to previously placed concrete of adequate strength, normally embedded in the concrete during placement.
a liquid applied to formwork surfaces to promote easy release from the concrete, preserve the form material, or retard setting of the near-surface matrix for preparation of exposed-aggregate finishes.
device used to support formwork from a structural framework (the dead load of forms, mass of concrete, and construction and impact loads must be supported).
insulating material applied to the outside of forms between studs and over the top in sufficient thickness and air tightness to conserve heat of hydration to maintain concrete at required temperatures in cold weather.
lateral pressure acting on vertical or inclined formed surfaces, resultingfrom the fluid-like behavior of the fresh concrete confined by the forms.
a mechanical connection in tension used to prevent concrete forms fromspreading due to the fluid pressure of fresh concrete.
total system of support for freshly placed concrete including the mold or sheathing that contacts the concrete as well as supporting members, hardware, and necessary bracing (also called shuttering in the United Kingdom). (See also falsework and centering
the number of frames of scaffolding erected one above the other.
a system of structural elements that transmits loads from the structure above to the earth.
(1) a crack or break in concrete or masonry; (2) the configuration of abroken surface; (3) the action of cracking or breaking. (See also crack.)
(1) descent of freshly mixed concrete into forms without dropchutes or other means of confinement; (2) the distance through which such descent occurs; (3) uncontrolled fall of aggregate.
(1) moisture having essentially the properties of pure water in bulk; (2) moisture not absorbed by aggregate. (See also surface moisture.)
concrete that possesses enough of its original workability that it can be placed and consolidated by the intended methods.
a thin steel trowel that is rectangular (with or without rounded corners), usually 4 to 10 in. (100 to 250 mm) wide and 20 to 36 in. (420 to 900 mm) long, with a 4 to 16 ft (1 to 5 m) long handle, and used to smooth surfaces of nonbleeding concrete and sh
an empirical curve for gradation of aggregates. (See also grading curve.)
